The present invention relates to novel diester and triester cationic lipids that can be used in combination with other lipid components such as cholesterol and PEG-lipids to form lipid nanoparticles with oligonucleotides, to facilitate the cellular uptake and endosomal escape, and to knockdown target mRNA both in vitro and in vivo.
Cationic lipids and the use of cationic lipids in lipid nanoparticles for the delivery of oligonucleotides, in particular siRNA and miRNA, have been previously disclosed. Lipid nanoparticles and use of lipid nanoparticles for the delivery of oligonucleotides, in particular siRNA and miRNA, have been previously disclosed. Oligonucleotides (including siRNA and miRNA) and the synthesis of oligonucleotides have been previously disclosed. (See US patent applications: US 2006/0083780, US 2006/0240554, US 2008/0020058, US 2009/0263407 and US 2009/0285881 and PCT patent applications: WO 2009/086558, WO2009/127060, WO2009/132131, WO2010/042877, WO2010/054384, WO2010/054401, WO2010/054405, WO2010/054406 and WO2011/153493). See also Semple S. C. et al., Rational design of cationic lipids for siRNA delivery, Nature Biotechnology, 2010, 28, 172-176.
Other cationic lipids are disclosed in the following patent applications: US 2009/0263407, US 2009/0285881, US 2010/0055168, US 2010/0055169, US 2010/0063135, US 2010/0076055, US 2010/0099738, US 2010/0104629, WO2010/088537, WO2010/144740, US2010/0324120, U.S. Pat. No. 8,034,376, WO2011/143230, WO2011/000106, US2011/0117125, US2011/0256175, WO2011/141703, WO2011/141704 and WO2011/141705.
Traditional cationic lipids such as CLinDMA and DLinDMA have been used for siRNA delivery to the liver but suffer from non-optimal delivery efficiency along with liver toxicity at higher doses. It is an object of the instant invention to provide a cationic lipid scaffold that demonstrates enhanced efficacy along with lower liver toxicity as a result of lower lipid levels in the liver. The present invention employs low molecular weight cationic lipids with one short lipid chain coupled with inclusion of hydrolysable functionality in the lipid chains to enhance the efficiency and tolerability of in vivo delivery of siRNA.